Trying To Identify the Manufacturer of a Piece

I'm desperately trying to figure out the manufacturer of a piece so that I might then discover how to fix a severe bathtub clog. The manner in which the linkage operates doesn't seem similar to that of any diagrams I've been able to find online or in books.

So can anyone tell me who made this quite old piece? (And if you know the exact term for the type of piece it is, that'd be great -- it doesn't operate in the traditional flip-lever capacity, so I'm not sure that's what to call this).

Well, it is called the waste and overflow trip lever. Obviously the eccentric cam causes the pin to move upward and downward. It should be linked to a barrel plug or some other device inside the overflow tube. It is possible that piece could be grabbed with pliers and removed.

I don't actually recognize the piece. From the "C" I would possibly think Crane. The styling of the chrome plate is consistent with that.